Image recording apparatus

ABSTRACT

An image recording apparatus includes a conveyance roller which conveys the recording medium, a drive source for rotating the conveyance roller, a print head and a carriage mounted with the print head. The carriage includes an abutment portion. The image recording apparatus further includes a carriage position detector which detects a position of the carriage in a movement direction of the carriage and still further includes a rotating body which rotates in synchronization with the conveyance roller. The rotating body includes a reference portion which protrudes or depresses in the movement direction at a predetermined rotation phase of the rotating body and abut with the reference portion. Moreover, the image recording apparatus includes an origin determination section which, based on a result of the detection by the carriage position detector, determines an origin position of a rotation phase of the conveyance roller.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims priority from Japanese Patent ApplicationNo. 2009-087970, filed on Mar. 31, 2009, the disclosure of which isincorporated herein by reference in its entirely.

BACKGROUND

1. Technical Field

The present invention relates to an image recording apparatus whichdetects an origin position of a rotation phase of a conveyance roller.

2. Related Art

An image recording apparatus is known on which a dedicated sensor whichdetects an origin position of a conveyance roller which conveys arecording sheet is provided in order to increase the conveyance accuracyof the conveyance roller and improve an image quality. However, whenproviding the dedicated sensor, there is a problem in that the apparatusincreases not only in cost, but also in size.

SUMMARY

A need has arisen to provide an image recording apparatus which canaccurately detect an origin position of a conveyance roller whilereducing an increase in size or cost of the apparatus.

According to an embodiment of the present invention, the image recordingapparatus comprises a conveyance roller which conveys the recordingmedium through a conveyance path in a conveyance direction. The imagerecording apparatus further comprises a drive source for rotating theconveyance roller and a synchronous shaft which rotates insynchronization with the conveyance roller. The image recordingapparatus still further comprises a rotation amount detector whichdetects a rotation amount of the synchronous shaft. Moreover, the imagerecording apparatus comprises a print head which executes an imagerecording on the recording medium conveyed by the conveyance roller anda carriage which, being mounted with the print head, moves in a movementdirection intersecting the conveyance direction. The carriage includesan abutment portion. The image recording apparatus further comprises acarriage position detector which detects a position of the carriage inthe movement direction and a rotating body which rotates insynchronization with the conveyance roller. The rotating body includes areference portion which protrudes or depresses in the movement directionat a predetermined rotation phase of the rotating body. The imagerecording apparatus still further comprises an origin determinationsection which moves the abutment portion of the carriage to a detectionposition where the abutment portion the reference portion of therotating body can make abutment with the abutment portion, drives thedrive source to rotate the conveyance roller and the rotating body, and,based on a result of the detection by the carriage position detector,determines an origin position of a rotation phase of the conveyanceroller.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, the needssatisfied thereby, and the features and advantages thereof, referencenow is made to the following descriptions taken in connection with theaccompanying drawings wherein:

FIG. 1 is a perspective view showing an external configuration of acomplex machine according to an embodiment of the invention;

FIG. 2 is a schematic diagram showing an internal configuration of aprinter;

FIG. 3 is a partial plan view showing the internal configuration of theprinter;

FIG. 4 is a partial perspective view showing the internal configurationof the printer;

FIG. 5 is a partial perspective view showing a configuration around atransmission gear;

FIG. 6 is an enlarged perspective view showing the configuration aroundthe transmission gear;

FIG. 7 is a block diagram showing a configuration of a controller;

FIG. 8A is a schematic diagram of an encoder disk and optical sensor;

FIG. 8B is a diagram illustrating an amount of conveyance of printingpaper per pulse signal output from a rotary encoder;

FIGS. 9A to 9D are diagrams for illustrating a process of acquiring acorrection value function A(θ);

FIGS. 10A and 10B are diagrams for illustrating the process of acquiringthe correction value function A(θ);

FIG. 11 is a flowchart illustrating a procedure of processes carried outin the complex machine when the complex machine is powered on; and

FIG. 12 is a flowchart illustrating a procedure of processes carried outin the complex machine when there is a recording start command.

DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

Embodiments of the invention and their features and advantages may beunderstood by referring to FIGS. 1-12, like numerals being used for likecorresponding parts in the various drawings. Referring now to thedrawings as needed, an embodiment of the invention will be described indetail.

Outline Configuration of Complex Machine 10

As shown in FIG. 1, a complex machine 10, integrally including a printer11 and a scanner 12, has a printing function, a scanning function, acopying function, and a facsimile function. The printer 11 is an exampleof an image recording apparatus. The complex machine 10 not necessarilyincluding the scanner 12. The image recording apparatus may also beimplemented as a single-function printer which does not have thescanning function or copying function. Consequently, a description of adetailed configuration of the scanner 12 is omitted here.

The printer 11 is provided in the lower portion of the complex machine10. An opening 13 is formed on the front side of the printer 11. A paperfeed cassette 21 and a paper feed cassette 22 are mounted in the printer11 through the opening 13. Standard-size rectangular printing paper 50is placed in the paper feed cassettes 21 and 22 (refer to FIG. 2). Withthe printer 11, the printing paper 50 is selectively fed into theprinter 11 from the paper feed cassette 21 or paper feed cassette 22.The printing paper 50, after an image is recorded thereon by a recordingsection 40 (refer to FIG. 2), is discharged onto a top surface 23 of thepaper feed cassette 22. The top surface 23 functions as a paperdischarge tray. The printing paper 50 is an example of a recordingmedium.

The complex machine 10 is used mainly in a condition in which it isconnected to external information equipment (not shown) such as acomputer. The printer 11, based on print data received from the externalinformation equipment, or on image data of a manuscript read by thescanner 12, records an image on the printing paper 50.

An operation panel 14 is provided on the upper front of the complexmachine 10. A display, which displays various kinds of information, andinput keys, which receive inputs of information, are provided on theoperation panel 14. The complex machine 10 operates based on instructioninformation input from the operation panel 14, or on instructioninformation transmitted from the external information equipment via aprinter driver, a scanner driver, or the like.

Printer 11

Hereafter, a description will be given, while referring to FIGS. 2 to 7as appropriate, of a configuration of the printer 11.

As shown in FIG. 2, the paper feed cassette 21 and paper feed cassette22 are disposed one on the other with the paper feed cassette 22 on theupper side. Both the paper feed cassette 21 and paper feed cassette 22hold the printing paper 50 on which an image recording is carried out.By the two independent paper feed cassettes 21 and 22 being provided,printing paper 50 of a differing size or type can be held in each ofthem.

The paper feed cassette 21 is a container-shaped one of which oneportion on the back side of the complex machine 10 is opened, and theprinting paper 50 is placed in a stacked condition in the internal spaceof the paper feed cassette 21. Printing paper 50 of various kinds ofsize such as, for example, an A4 size, a B5 size, and a postcard size,which are smaller than an A3 size, can be contained in the paper feedcassette 21.

The paper feed cassette 22 is a container-shaped one of which oneportion on the back side (the right side in FIG. 2) of the complexmachine 10 is opened, and the printing paper 50 is placed in a stackedcondition in the internal space of the paper feed cassette 22. Printingpaper 50 of various kinds of size such as, for example, an A4 size, a B5size, and a postcard size, which are smaller than an A3 size, can becontained in the paper feed cassette 22. The top surface 23 of the paperfeed cassette 22 is provided on the front side (the left side in FIG. 2)of the complex machine 10.

First Feed Section 28

A conveyance path 18 formed in a curved shape is provided on the upperside of an inclined plate 24 of the paper feed cassette 22. On the paperfeed cassette 22 being mounted in the printer 11, the inclined plate 24is disposed below the conveyance path 18, and a first feed section 28 isdisposed on the upper side of the paper feed cassette 22. The first feedsection 28 includes a feed roller 25, an arm 26, and a shaft 27. Thefeed roller 25 is rotatably provided on the leading end side of the arm26. The arm 26 is pivotably provided on the shaft 27 supported on ahousing of the printer 11. The arm 26 is pivotally biased toward thepaper feed cassette 22 side by its own weight or under the elastic forceof a spring or the like.

Second Feed Section 38

A conveyance path 17 formed in a curved shape is provided on the upperside of an inclined plate 34 of the paper feed cassette 21. On the paperfeed cassette 21 being mounted in the printer 11, the inclined plate 34is disposed below the conveyance path 17, and a second feed section 38is disposed on the upper side of the paper feed cassette 21. The secondfeed section 38 includes a feed roller 35, an arm 36, and a shaft 37.The feed roller 35 is rotatably provided on the leading end side of thearm 36. The arm 36 is pivotably provided on the shaft 37 supported onthe housing of the printer 11. The arm 36 is pivotally biased toward thepaper feed cassette 21 side by its own weight or under the elastic forceof a spring or the like.

Conveyance Paths 17, 18, and 19

A conveyance path 19 continuous with the conveyance path 17 andconveyance path 18 is provided inside the printer 11. The conveyancepath 19, being a path along which is conveyed the printing paper 50conveyed along the conveyance path 17 or conveyance path 18, is extendedfrom a position in which the conveyance path 17 and conveyance path 18meet, toward the front side of the complex machine 10, as far as aposition above the top surface 23 of the paper feed cassette 22.

Platen 43

A platen 43 (refer to FIGS. 2 and 3) is provided in the conveyance path19. The platen 43 supports the printing paper 50, conveyed along theconveyance path 19, from below. The recording section 40 is disposed onthe upper side of the platen 43. The recording section 40 will bedescribed hereafter.

As shown in FIGS. 4 and 5, a waste ink tray 66 is provided on a sidewhich is one end of the platen 43 in a width direction 121, and on whicha transmission gear 77 (refer to FIG. 3), to be described hereafter, isdisposed. The waste ink tray 66 receives ink droplets ejected from aprint head 42 for the purpose of maintenance. The waste ink tray 66 isof a tray shape corresponding to a nozzle area of the print head 42, andthe internal space thereof is filled with an ink absorbent. The inkabsorbent absorbs and holds the ink droplets ejected from the print head42. For example, in the event that a purging is carried out, and ink inthe nozzle area is wiped out by a wiper, there is a risk of a slightamount of ink of other than an appropriate ink color being trapped intoeach nozzle orifice, or a risk of the meniscus of ink in each nozzleorifice taking on an abnormal condition. Consequently, by ejecting inkdroplets from all the nozzle orifices of the print head 42 after thepurging, the trapped ink is discharged, or the meniscus of ink in eachnozzle orifice is restored to a normal condition. In the presentspecification, this kind of operation of ejecting ink droplets is calleda flushing.

Conveyance Roller Pair 59

A conveyance roller pair 59 is provided on a side upstream of the platen43 in a conveyance direction 124 of the printing paper 50. Theconveyance roller pair 59 is configured of a conveyance roller 60 and apinch roller 61. The conveyance roller 60, being disposed on the upperside of the conveyance path 19, rotates under a drive force from an LFmotor 85 (an example of a drive source) shown in FIG. 6. The pinchroller 61, being rotatably disposed on the lower side of the conveyanceroller 60 across the conveyance path 19, is biased by a spring towardthe conveyance roller 60.

Discharge Roller Pair 64

A discharge roller pair 64 is provided on a side downstream of theplaten 43 in the conveyance direction 124 of the printing paper 50. Thedischarge roller pair 64 is configured of a discharge roller 62 and aspur wheel 63. The discharge roller 62, being disposed on the lower sideof the conveyance path 19, rotates under the drive force from the LFmotor 85 (refer to FIG. 6). The spur wheel 63, being rotatably disposedon the upper side of the discharge roller 62 across the conveyance path19, is biased by a spring toward the discharge roller 62.

Encoder Disk 71 and Optical Sensor 55

As shown in FIGS. 3 to 6, an encoder disk 71 is provided on a shaft 76of the conveyance roller 60. The encoder disk 71 being a transparentdisk-shaped disk, light blocking marks are made thereon at apredetermined pitch in a circumferential direction. The encoder disk 71,being fixed to the shaft 76 of the conveyance roller 60, rotatestogether with the conveyance roller 60. The optical sensor 55 includes alight emitting element and a light receiving element, facing each other,spaced a predetermined distance apart in the width direction 121. Theoptical sensor 55 is provided in such a way that the peripheral edge ofthe encoder disk 71 is positioned in a space between the light emittingelement and light receiving element. On light being received by thelight receiving element of the optical sensor 55, an electrical signalwith a level corresponding to the luminance of the light received isgenerated in the optical sensor 55. An electrical signal with a lowlevel is generated in a condition in which a mark is positioned betweenthe light emitting element and light receiving element. An electricalsignal with a high level is generated in a condition in which no mark ispositioned between the light emitting element and light receivingelement. That is, a pulse signal is generated every time a mark of theencoder disk 71 is detected by the optical sensor 55. The pulse signalis output to a controller 100. A first detection unit is realized by theencoder disk 71 and optical sensor 55.

Recording Section 40

As shown in FIGS. 2 to 4, the recording section 40 is disposed above theplaten 43, facing the platen 43, spaced a predetermined distance awayfrom the platen 43. That is, the recording section 40 is disposeddownstream of the conveyance roller pair 59 in the conveyance direction124. The recording section 40 includes the ink-jet recording type ofprint head 42 and a carriage 41.

Carriage 41

As shown in FIG. 4, the carriage 41 forms a parallelepiped shape. Theprint head 42, being mounted on the carriage 41, is exposed on thebottom side thereof. The carriage 41 can move in the width direction 121along guide frames 44 and 45, to be described hereafter. An abutmentportion 53 protruding in the width direction 121 is provided on a sidesurface, of the two side surfaces of the carriage 41 opposed in thewidth direction 121, which faces the transmission gear 77 (refer to FIG.3). A reference portion 80, to be described hereafter, of thetransmission gear 77 can make abutment with the abutment portion 53.

Guide Frames 44 and 45

As shown in FIGS. 3 and 4, the pair of guide frames 44 and 45 isprovided, on the upper side of the conveyance path 19, spaced apredetermined distance apart in the conveyance direction 124. The guideframes 44 and 45 are provided extending in the width direction 121. Theguide frame 44 is provided on a side upstream of the guide frame 45 inthe conveyance direction 124. The carriage 41 is placed on the guideframes 44 and 45 in such a way as to bridge the guide frames 44 and 45.The carriage 41 faces the platen 43 across the conveyance path 19. InFIG. 2, the guide frames 44 and 45 are omitted.

An end portion of the carriage 41 on the upstream side in the conveyancedirection 124 is slidably supported on the top surface of the guideframe 44. An end portion of the carriage 41 on the downstream side inthe conveyance direction 124 is slidably supported on the top surface ofthe guide frame 45. An end portion 39 of the guide frame 45, being aportion of the guide frame 45 bent upward at approximately a rightangle, is extended in the width direction 121. The carriage 41 holds theend portion 39 between its unshown rollers or the like. Therefore, thecarriage 41 moves in the width direction 121 with the end portion 39 asa reference.

Belt Drive Mechanism 46

As shown in FIGS. 3 and 4, a belt drive mechanism 46 is provided on thetop surface of the guide frame 45. The belt drive mechanism 46 includesa drive pulley 47, a driven pulley 48, and a belt 49. The drive pulley47 and driven pulley 48 are provided one in the vicinity of either endof the guide frame 45 in the width direction 121. The belt 49, being anendless annular belt on the inner side of which teeth are provided, isstretched between the drive pulley 47 and driven pulley 48.

A CR motor 86 (refer to FIG. 4) is connected to the shaft of the drivepulley 47. The drive pulley 47 rotates under the drive force of the CRmotor 86. The belt 49 moves circularly by means of the rotative force ofthe drive pulley 47. As the carriage 41 is fixed to the belt 49, itmoves in the width direction 121 by the belt 49 moving circularly.

Encoder Strip 51 and Optical Sensor 52

As shown in FIGS. 3 and 4, an encoder strip 51 is provided on the guideframe 45. The encoder strip 51 is provided stretched over a movementrange of the carriage 41 in the width direction 121. The encoder strip51 is a strip-shaped one made of a transparent resin. A pattern in whichlight blocking portions, which block light, and light transmissionportions, which transmit light, are alternately arranged at equalpitches is formed on the encoder strip 51. An optical sensor 52 fordetecting the pattern of the encoder strip 51 is mounted on the carriage41.

The optical sensor 52 includes a light emitting element and a lightreceiving element, facing each other, spaced a predetermined distanceapart in a depth direction 123. The optical sensor 52 is provided insuch a way that the encoder strip 51 is positioned in a space betweenthe light emitting element and light receiving element. On light beingreceived by the light receiving element of the optical sensor 52, anelectrical signal with a level corresponding to the luminance of thelight received is generated in the optical sensor 52. An electricalsignal with a low level is generated in a condition in which a mark ispositioned between the light emitting element and light receivingelement. An electrical signal with a high level is generated in acondition in which no mark is positioned between the light emittingelement and light receiving element. That is, a pulse signal isgenerated every time a mark of the encoder strip 51 is detected by theoptical sensor 52. The pulse signal is output to the controller 100. Aposition detection unit is realized by the encoder strip 51 and opticalsensor 52.

Print Head 42

As shown in FIGS. 2 and 4, nozzles of the print head 42 are exposed inthe second surface of the carriage 41. A large number of nozzles arearrayed in the width direction 121 and depth direction 123. Ink issupplied to the print head 42 from an ink cartridge (not shown) disposedinside the printer 11. The carriage 41 is moved in the width direction121 when the conveyance roller 60 and discharge roller 62 intermit tocause the printing paper 50 to remain stationary on the platen 43. Theprint head 42 is also moved in the width direction together with thecarriage 41 and, during the movement, minute ink droplets are ejectedselectively from the nozzles of the print head 42 toward the printingpaper 50 on the platen 43. Then, the printing paper 50 is conveyed apredetermined linefeed width in the conveyed direction 124 by theconveyance roller pair 59 and discharge roller pair 64. An image isrecorded on the printing paper 50 by the print head 42 while this kindof intermittent conveyance of the printing paper 50 and the movement ofthe carriage 41 are being alternately repeated.

LF Motor 85

As shown in FIG. 6, the LF motor 85 is provided in the printer 11. TheLF motor 85 rotates the conveyance roller 60 and discharge roller 62while controlling the rotation thereof. The LF motor 85 includes, forexample, a DC motor. The LF motor 85 corresponds to the drive source forthe conveyance roller 60.

An output shaft 75 of the LF motor 85, having spur teeth formed on theouter periphery thereof, meshes with the transmission gear 77. Thetransmission gear 77, being a spur gear, and coaxially connected to theshaft 76 of the conveyance roller 60, rotates in synchronization withthe shaft 76. The rotation of the LF motor 85 is transmitted to theshaft 76 of the conveyance roller 60 by the transmission gear 77. Thetransmission gear 77 corresponds to a rotating body.

The transmission gear 77 is meshed with a transmission gear 78. Unshownadditional transmission gears are connected in series to thetransmission gear 78, and finally connected to the shaft of thedischarge roller 62. Therefore, the rotation of the LF motor 85 is alsotransmitted to the shaft of the discharge roller 62, and the conveyanceroller 60 and discharge roller 62 are rotated in synchronization.

The conveyance roller 60 and discharge roller 62 are intermittentlydriven by the LF motor 85 when an image recording by the recordingsection 40 is carried out. The intermittent drive is a drive methodwhereby the LF motor 85 is continuously driven until the conveyanceroller 60 and discharge roller 62 rotate by a rotation amount equivalentto a predetermined target conveyance amount while, on the targetconveyance amount being reached, the LF motor 85 is stopped for apredetermined time, and these operations are repeated alternately.

On the printing paper 50 fed to the conveyance path 19 arriving betweenthe conveyance roller 60 and pinch roller 61, the printing paper 50 isejected onto the platen 43 under the rotative force of the conveyanceroller 60 on a condition that the printing paper 50 is held between theconveyance roller 60 and pinch roller 61. On the printing paper 50reaching a position between the discharge roller 62 and spur wheel 63,the printing paper 50 is ejected to a position above the paper feedcassette 22 under the rotative force of the discharge roller 62 on acondition that the printing paper 50 is held between the dischargeroller 62 and spur wheel 63.

In this way, the printing paper 50 is conveyed on the platen 43 underthe rotative force of at least one of the conveyance roller 60 anddischarge roller 62. At this time, as the conveyance roller 60 anddischarge roller 62 are being intermittently driven, the printing paper50 is intermittently conveyed along the conveyance path 19. Then, theimage recording by the recording section 40 is carried out while theprinting paper 50 is being caused to remain stationary on the platen 43during the intermittent conveyance.

The conveyance roller 60 and discharge roller 62 do not have to beintermittently driven while no image recording is being carried out bythe recording section 40. Consequently, the conveyance roller 60 anddischarge roller 62 may be continuously rotated before a recordingoperation by the print head 42 is started, or after the recordingoperation is completed.

Transmission Gear 77

As shown in FIGS. 5 and 6, the reference portion 80 is provided on asurface 79 of the transmission gear 77 facing the carriage 41 side. Thereference portion 80, being disposed at a predetermined rotation phaseof the transmission gear 77, is protruded from the surface 79 in thewidth direction 121, which is a direction of movement of the carriage41. The reference portion 80 has inclined surfaces 81 and 82, whichcontinue to the surface 79 at a predetermined inclination angle thereto,and a surface 83 which, being disposed between the inclined surfaces 81and 82, is parallel to the surface 79. The inclined surfaces 81 and 82are surfaces inclined largely in the circumferential direction of thetransmission gear 77.

As shown in FIGS. 3 and 4, the transmission gear 77 is disposed in thewidth direction 121 with respect to the carriage 41 on a condition thatthe carriage 41 is assembled to the guide frames 44 and 45, and thelike. In the event of seeing the transmission gear 77 from a line ofsight 125 in the width direction 121, the reference portion 80, by thetransmission gear 77 being rotated, passes through a projection plane ofthe carriage 41 in the width direction 121. That is, the referenceportion 80 can make abutment with the abutment portion 53 of thecarriage 41 on a condition that the carriage 41 is moved to theimmediate lateral side of the transmission gear 77.

Controller 100

The controller 100 shown in FIG. 7 not only controls the printer 11, butconducts an overall control of the whole operation of the complexmachine 10. The controller 100 is configured as a microcomputerprincipally including a CPU 101, an ROM 102, an RAM 103, an EEPROM 104,and an application specific integrated circuit (ASIC) 109. Thecontroller 100 functions as the second detection unit, a correctionunit, and a control unit. In FIG. 7, a path of transmission of a driveforce from each motor 85, 86, and 87 is shown by the broken lines.

A program, or the like, for the CPU 101 to control the motors 85, 86,and 87, and complex machine 10 is stored in the ROM 102. The RAM 103 isused as a storage area in which are temporarily stored various kinds ofdata used when the CPU 101 executes the program, or as a working areafor data processing or the like. A current rotation phase (hereafterreferred to as a “current phase θ”) of the conveyance roller 60 isstored in the RAM 103. The current phase θ is appropriately renewedevery time the conveyance roller 60 is rotated. The EEPROM 104 stores asetting, a flag, or the like, which is to be held even after poweringoff. A correction value function A(θ), to be described hereafter, isstored in the EEPROM 104. The correction value function A(θ) is afunction which regulates a correlation between the rotation phase of theconveyance roller 60 and a correction value of an amount of conveyanceof the printing paper 50 per rotation phase of the conveyance roller 60.That is, in the embodiment, the EEPROM 104 functions as a storage unit.

Drive circuits 72, 73, and 74, a linear encoder 88 (an example of acarriage position detector), and a rotary encoder 89 (an example of arotation amount detector) are connected to the ASIC 109. The scanner 12,operation panel 14, and the like, are connected to the controller 100.

The drive circuit 72 drives the LF motor 85. The shaft 76 of theconveyance roller 60 and the shaft of the discharge roller 62 areconnected to the LF motor 85 via the transmission gears 77 and 78, andthe like. The drive circuit 72 drives the LF motor 85 by receiving anoutput signal from the ASIC 109. The drive force of the LF motor 85 istransmitted to the shaft 76 and the like, and the conveyance roller 60and discharge roller 62 rotate in synchronization. The printing paper 50fed to the conveyance path 19, after being conveyed along the conveyancepath 19 under the rotative force of the conveyance roller 60 ordischarge roller 62, is discharged onto the top surface 23 of the paperfeed cassette 22.

The drive circuit 73 drives the CR motor 86 by receiving an outputsignal from the ASIC 109. The drive force of the CR motor 86 istransmitted to the carriage 41 via the belt drive mechanism 46.Therefore, the carriage 41 moves in the width direction 121.

The drive circuit 74 drives the ASF motor 87. The ASF motor 87 isconnected to the feed roller 25 or feed roller 35 via an unshown drivetransmission mechanism. The drive circuit 74 rotates the ASF motor 87 byreceiving an output signal from the ASIC 109. Then, the drivetransmission mechanism transmits the drive force of the ASF motor 87selectively to the feed roller 25 or feed roller 35. A topmost sheet ofprinting paper 50 in the paper feed cassette 21 or paper feed cassette22 is fed to the conveyance paths 18 and 19 under the rotative force ofthe feed roller 25 or feed roller 35.

The linear encoder 88 detects the pattern of the encoder strip 51 bymeans of the optical sensor 52 mounted on the carriage 41, and outputs apulse signal. The controller 100, based on the output pulse signal,determines the speed and position of the carriage 41, and controls thedrive of the CR motor 86. Also, as will be described hereafter, thecontroller 100 determines the origin position of the conveyance roller60 based on the fact that a movement of the carriage 41 has beendetected based on the pulse signal from the linear encoder 88.

The rotary encoder 89 detects a mark of the encoder disk 71 by means ofthe optical sensor 55, and outputs a pulse signal. The controller 100,based on the output pulse signal, determines a rotation amount of theconveyance roller 60, and controls the drive of the LF motor 85.

However, in order for the printing paper 50 to be conveyed with highaccuracy in the printer 11, it is preferable that linearity isestablished between the rotation amount of the conveyance roller 60detected by the rotary encoder 89 and an actual rotation amount of theconveyance roller 60. A condition in which an eccentric encoder disk 71is attached to the shaft 76 of the conveyance roller 60 is shown in FIG.8A. Due to this kind of eccentricity of the encoder disk 71, a warpageor uneven coating thickness of the conveyance roller 60, an eccentricityof the transmission gear 77 meshed with the shaft 76 of the conveyanceroller 60, or the like, a rotation amount of the conveyance roller 60per rotation phase detected by the rotary encoder 89 fluctuatescyclically with one revolution of the conveyance roller 60 as one cycle(refer to FIG. 8B). In the example shown in FIGS. 8A and 8B, when aposition B of the encoder disk 71 is detected, an amount of conveyanceof the printing paper 50 per pulse signal output from the rotary encoder89 is large. Contrarily, when a position D of the encoder disk 71 isdetected, the amount of conveyance of the printing paper 50 per pulsesignal output from the rotary encoder 89 is small. In this way, theamount of conveyance of the printing paper 50 by the conveyance roller60 fluctuates cyclically.

For this reason, the controller 100 (an example of a correctionsection), in order to control the cyclical fluctuation in the amount ofconveyance by the conveyance roller 60, controls the drive of the LFmotor 85, and corrects the rotation amount of the conveyance roller 60in such a way that the rotation amount is uniform. The correction valuefunction A(θ) used for correction processing of the rotation amount isstored in the EEPROM 104. Hereafter, a description will be given of aprocess of acquiring the correction value function A(θ). The correctionvalue function A(θ) may be acquired and written in advance on the EEPROM104 before a factory shipment of the complex machine 10. However, thecorrection value function A(θ) may also be written on the EEPROM 104 bya user executing a predetermined operation in accordance with a manualor instructions displayed on the operation panel 14 when starting usingthe complex machine 10.

Acquisition of Correction Value Function A(θ)

In the embodiment, the conveyance roller 60 is configured in such a waythat the printing paper 50 is ejected 1.2 inches when the conveyanceroller 60 rotates one revolution. Also, it is taken that a nozzledensity of the print head 42 in the conveyance direction 124 is 150 dpi,and that 8640 pulse signals are output from the rotary encoder 89 whenthe encoder disk 71 rotates one revolution.

The controller 100 controls the drive of the ASF motor 87, and feeds theprinting paper 50 from the paper feed cassette 21 or paper feed cassette22 to the conveyance path 19. Then, the controller 100 controls theoperation of the recording section 40, causing the recording section 40to record one line long in the width direction 121 on the leading endside of the printing paper 50 (refer to FIG. 9A). Specifically, thecontroller 100, while moving the carriage 41 a first distance from oneend side to the other end side in the width direction 121, ejects inkfrom the nozzles farthest upstream (first nozzles) in the conveyancedirection 124 of the print head 42. On one long line being drawn on theleading end side of the printing paper 50 in this way, the controller100 controls the drive of the LF motor 85, and conveys the printingpaper 50 by an amount equivalent to 0.57 inches' worth of pulse signals.Specifically, the controller 100 drives the LF motor 85 until 4104(=8640×0.57/1.2) pulse signals are output from the rotary encoder 89,and conveys the printing paper 50 to the conveyance roller 60. The LFmotor 85 is stopped after the number of pulse signals output from therotary encoder 89 reaches 4104.

Next, the controller 100 causes the recording section 40 to record oneline short in the width direction 121 on the printing paper 50 (refer toFIG. 9B). Specifically, the controller 100, while moving the carriage 41a second distance, which is shorter than the first distance, from oneend side to the other end side in the width direction 121, ejects inkfrom the 91st nozzles from the nozzles farthest upstream in theconveyance direction 124 of the print head 42. As the density of theprint head 42 in the conveyance direction 124 is 150 dpi, a distance inthe conveyance direction 124 between the first nozzles and 91st nozzlesis 0.6 (=(91−1)/150) inches. For this reason, the 91st nozzles andaforementioned long line are ideally spaced 0.03 (=0.6−0.57) inchesapart in the conveyance direction 124.

The controller 100 repeats the operation of causing the recordingsection 40 to draw the short line and the operation of causing the LFmotor 85 to convey the printing paper 50 by an amount equivalent to 0.01inches' worth of pulse signals (=8640×0.01/1.2) alternately. By thismeans, seven short lines are recorded on the printing paper 50 (refer toFIG. 9C). The recording operation by the print head 42 is carried outwhile a position of the carriage 41 in the width direction 121 is beingchanged in such a way that positions of the seven short lines in thewidth direction 121 differ.

Then, the controller 100 causes another long line to be recorded in aposition in which the printing paper 50 is advanced 0.1 inches, andrepeats the process of recording the seven short lines with respect tothe long line (refer to FIG. 9D). By this kind of process of recordingthe one long line and seven short lines being repeated as one pattern, atotal of 12 patterns are recorded on the printing paper 50 (refer toFIG. 10A).

Continuing, it is determined in each pattern what number short line ismost exactly superimposed on the long line, or whether the long line isbetween adjacent short lines. Specifically, the printing paper 50 isplaced on contact glass of the scanner 12, and the scanner 12 is causedto execute an image reading from the printing paper 50. Then, thecontroller 100 determines what number short line is most exactlysuperimposed on the long line, or whether the long line is betweenadjacent short lines. This determination process is carried out in eachpattern. In the event of the printing paper 50 shown in FIG. 10A,numerical values can be determined to be 3, 2.5, 2, 3, 4, 4, 5, 6, 6.5,6, 4, and 3.5 in order from the topside long line in the FIG. 10A. Inthe event that the long line is between two adjacent short lines, thedetermination is made by adding 0.5 to the number of the line of the twoadjacent short lines with the smallest number.

The first nozzle and 91st nozzle are spaced 0.6 inches apart in theconveyance direction 124. For this reason, in the event that thenumerical value is 4, it indicates that the printing paper 50 hasactually been conveyed 0.6 (=0.57+0.01×(4−1)) inches with respect to atarget conveyance amount of 0.6 inches. In the event that the numericalvalue is 3, it indicates that the printing paper 50 has actually beenconveyed 0.6 inches with respect to a target conveyance amount of 0.59(=0.57+0.01×(3−1)) inches. This represents that the printing paper 50has been conveyed by a peripheral surface of the conveyance roller 60 ona position B side in FIG. 8A. In the event that the numerical value is5, it indicates that the printing paper 50 has actually been conveyed0.6 inches with respect to a target conveyance amount of 0.61(=0.57+0.01×(5−1)) inches. This represents that the printing paper 50has been conveyed by a peripheral surface of the conveyance roller 60 ona position D side in FIG. 8A.

A graph equivalent to that of FIG. 8B can be obtained (refer to FIG.10B) by allotting pulse numbers to the horizontal axis in increments of1/12 revolution (720 pulses), and representing a conveyance amount perpulse number as a ratio thereof to a target conveyance amount in thevertical axis. That is, it is possible to ascertain how the amount ofconveyance of the printing paper 50 differs from the target conveyanceamount while the conveyance roller 60 is rotating one revolution.

How much the current encoder disk 71 rotates with respect to a rotationphase of the encoder disk 71 when a first long line is recorded when thepatterns shown in FIG. 10A are recorded on the printing paper 50 can beascertained as long as a rotation of the conveyance roller 60 isdetected by the rotary encoder 89. Consequently, the cyclicalfluctuation in the amount of conveyance of the printing paper 50 can besuppressed by, when a command to convey the printing paper 50 is input,calculating from the previously described graph an average difference inthe amount of conveyance by the conveyance roller 60 from a currentposition to a position after a completion of the conveyance, andcorrecting a target conveyance amount by taking into account an effectof the average difference in advance.

The rotation phase of the encoder disk when the first long line isrecorded matches the origin position of the conveyance roller, to bedescribed hereafter, or is regulated in a position with a predeterminedphase difference from the origin position. In the embodiment, thecorrection value function A(θ) for correcting the target amount ofconveyance of the printing paper 50 is generated based on the graphshown in FIG. 10B, and stored in the EEPROM 104. For this reason, evenin the event that the complex machine 10 is powered on again after beingpowered off, it is possible, by detecting a physical origin of therotation phase of the conveyance roller 60, to appropriately correct therotation amount of the conveyance roller 60.

Acquisition of Origin Position

Hereafter, a description will be given, while referring to the flowchartof FIG. 11, of a procedure of processes carried out in the printer 11when the complex machine 10 is powered on. The following processes to bedescribed based on the flowchart are carried out in accordance withcommands which the controller 100 (an example of an origin determinationsection) issues based on the program stored in the ROM 102.

The controller 100, based on an existence or otherwise of an operationof a predetermined input key of the operation panel 14, determineswhether or not the complex machine 10 has been powered on (S1). If thecontroller 100 determines that the complex machine 10 has not beenpowered on (S1: No), a waiting condition starts. If the controller 100determines that the complex machine 10 has been powered on (S1: Yes), itcontrols the drive circuit 73, and drives the CR motor 86 (S2). On thecomplex machine 10 being powered off, the controller 100 moves thecarriage 41 to a home position. The home position is an end on a sideopposite to the transmission gear 77 (the right side in FIG. 3) in areciprocation range of the carriage 41. An end of the carriage 41reciprocation range on a side on which the transmission gear 77 isdisposed is called an end position (the left side in FIG. 3). The endposition is an example of a detection position.

On the CR motor 86 being driven, the carriage 41 positioned in the homeposition moves toward the end position. The controller 100, based on aresult of detection by the linear encoder 88, determines whether or notthe carriage 41 has reached the end position (S3). The CR motor 86 isdriven until the carriage 41 reaches the end position. Then, on thecarriage 41 reaching the end position (S3: Yes), the controller 100stops the CR motor 86 (S4).

On the carriage 41 being positioned in the end position, the controller100 executes the flushing (S5). The flushing need not necessarily becarried out but, in the event that a time for which the carriage 41 isstopped in the end position is long in a subsequent operation, it ispreferable that the flushing is always carried out in order to preventor reduce a drying or nozzle clogging of the print head 42 during thestopping time. This flushing operation is appropriately carried outduring the subsequent processes too.

The controller 100 drives the LF motor 85 on a condition that the CRmotor 86 is not driven (S6). On the LF motor 85 being driven, thetransmission gear 77 rotates, and the conveyance roller 60 and dischargeroller 62 also rotate. As the carriage 41 is positioned in the endposition, on the transmission gear 77 attaining the predeterminedrotation phase, the reference portion 80 makes abutment with theabutment portion 53 of the carriage 41. Specifically, one of theinclined surfaces 81 and 82 of the reference portion 80 makes abutmentwith the carriage 41 and, by the transmission gear 77 being furtherrotated, the abutment portion 53 of the carriage 41 moves from one ofthe inclined surfaces 81 and 82 of the transmission gear 77 toward thesurface 83. Therefore, the carriage 41 positioned in the end position ismoved in such a way as to be pushed to the home position side by thereference portion 80. This kind of abutment of the reference portion 80with the abutment portion 53 of the carriage 41 may occurs once everytime the transmission gear 77 is rotated one revolution.

The controller 100 monitors a change of the linear encoder 88 while theLF motor 85 is being driven (S7). As previously described, on thecarriage 41 positioned in the end position moving to the home positionside, a pulse signal is output from the linear encoder 88. Thecontroller 100 detects, as the origin position of the conveyance roller60, a rotation phase θ₀ of the rotary encoder 89 when the pulse signalis output from the linear encoder 88 (S8). Information indicating theorigin position of the conveyance roller 60 is stored in the RAM 103. Inthe event that no pulse signal is output from the linear encoder 88 (S7:No), and the conveyance roller has not rotated one revolution (S11: No),the controller 100 continues to monitor an output from the linearencoder 88.

Continuing, the controller 100, based on a result of detection by therotary encoder 89, and on the information indicating the origin positionstored in the RAM 103, determines whether or not the current rotationphase of the conveyance roller 60 has reached the origin position (S9).If the controller 100 determines that the rotation phase of theconveyance roller 60 has not reached the origin position (S9: No), thecontroller 100 drives the LF motor 85 until the rotation phase of theconveyance roller 60 reaches the origin position. If the controller 100determines that the rotation phase of the conveyance roller 60 hasreached the origin position (S9: Yes), it stops the LF motor 85 (S10).

However, as previously described, it may happen that the abutmentportion 53 of the carriage 41 makes abutment with the surface 83 of thereference portion 80 of the transmission gear 77 when the carriage 41 ispositioned in the end position (S3). In this kind of case, even in theevent that the LF motor 85 is subsequently driven and the transmissiongear 77 is rotated one revolution or more, the carriage 41 is not movedto the home position side. That is, the linear encoder 88 outputs nopulse signal (S7: No).

In the event that the conveyance roller 60 is rotated one revolutionwithout the linear encoder 88 outputting any pulse signal (S11: Yes),specifically, in the event that the controller 100 determines that thenumber of pulse signals output from the rotary encoder 89 has reached8640, the controller 100, after rotating the conveyance roller 60another 1/N (N is a positive integer other than 1) of one revolution(S12), stops the LF motor 85 (S13). Therefore, the carriage 41 isstopped in a rotation position in which the reference portion 80 makesno contact with the abutment portion 53 of the carriage 41. It issufficient that a rotation amount of 1/N of one revolution by which theconveyance roller 60 is rotated is optionally set, provided that it isother than an integral multiple of one cycle.

Continuing, the controller 100 returns the carriage 41 to the homeposition temporarily (S14), and positions the carriage 41 in the endposition again (S3). Therefore, the carriage 41 is positioned in the endposition on a condition that the abutment portion 53 of the carriage 41is not in abutment with the surface 83 of the reference portion 80 ofthe transmission gear 77. Consequently, the origin position of theconveyance roller 60 is reliably detected by the same operation aspreviously described being carried out.

Printing Paper 50 Conveyance Operation

Hereafter, a description will be given, while referring to the flowchartof FIG. 12, of a procedure of processes carried out in the printer 11when a recording start command is input into the complex machine 10.

The controller 100 determines whether or not there is a recording startcommand (S21). Specifically, the controller 100 determines whether ornot a command to instruct a recording start, and print data, have beenreceived from the external information equipment, or whether or not anoperation input instructing a recording start has been carried out onthe operation panel 14. If the controller 100 determines that there isno recording start command (S21: No), a waiting condition starts.

If the controller 100 determines that there is a recording start command(S21: Yes), the controller 100 retrieves the correction value functionA(θ) from the EEPROM 104 (S22). The controller 100 further retrieves thecurrent phase θ of the conveyance roller 60 from the RAM 103 (S23). Thecurrent phase θ indicates a rotation direction angle from the originposition of the conveyance roller 60. Next, the controller 100 acquiresa target rotation amount Xm which is the number of pulse signals to beoutputted from the rotary encoder 89 while conveying the printing paper50 to a target position (S24). Then, the controller 100 substitutes thecurrent phase θ for the correction value function A(θ) retrieved in stepS22, and calculates a correction value C representing the number ofpulse signals (S25).

The controller 100 adds the correction value C to the target rotationamount Xm acquired in the process of step S24, and corrects the targetrotation amount Xm (S26). Then, the controller 100, based on thecorrected target rotation amount Xm, renews the current phase θ (S27).As the current phase θ is the rotation direction angle of the conveyanceroller 60, in the event that the value thereof exceeds 2π, 2π issubtracted from the value. By this means, the value of the current phaseθ is adjusted in such a way that the current phase θ always satisfiesthe relationship 0≦θ≦2π.

Next, the controller 100 drives the LF motor 85 (S28). Then, thecontroller 100 determines whether or not the rotation amount of theconveyance roller 60 detected by the rotary encoder 89 has reached thetarget rotation amount Xm corrected by the process of step S26 (S29).Specifically, the controller 100 determines whether or not the number ofpulse signals output from the rotary encoder 89 has reached the targetrotation amount Xm. If the controller 100 determines that the rotationamount of the conveyance roller 60 has not reached or will not reach thetarget rotation amount Xm (S29: No), the process is returned to stepS28. That is, the LF motor 85 is driven until the rotation amount of theconveyance roller 60 reaches the target rotation amount Xm.

While the conveyance roller 60 is moving, a cyclical difference with onerevolution as one cycle occurs between the rotation amount of theconveyance roller 60 detected by the rotary encoder 89 and the actualrotation amount of the conveyance roller 60. In the embodiment, thecurrent phase of the conveyance roller 60 is determined based on theorigin position of the conveyance roller 60 acquired after the complexmachine 10 is powered on, and the target rotation amount Xm is correctedbased on the correction value C corresponding to the current phase. Asthe drive of the LF motor 85 is controlled in such a way that therotation amount of the conveyance roller 60 complies with the targetrotation amount Xm after the correction, the cyclical difference in therotation amount of the conveyance roller 60 is balanced out, and theprinting paper 50 is accurately conveyed to a targeted position.

If the controller 100 determines that the rotation amount of theconveyance roller 60 has reached or will reach the target rotationamount Xm (S29: Yes), the controller 100 stops the LF motor 85 (S30).Then, the controller 100 causes the recording section 40 to execute animage recording (S31). Specifically, the controller 100 ejects ink fromthe print head 42 while moving the carriage 41 from one end side to theother end side in the width direction 121.

The controller 100 determines whether or not the printing paper 50conveyance operation is completed (S32). If the controller 100determines that the printing paper 50 conveyance operation is notcompleted (S32: No), the process is returned to step S24. That is, theprocesses of step S24 to step S29 are repeated. By this means, as theprocess of rotating the conveyance roller 60 by the target rotationamount Xm, and the process of recording an image on the printing paper50, are repeated alternately, continuous images are recorded on theprinting paper 50. If the controller 100 determines that the printingpaper 50 conveyance operation is completed (S32: Yes), the series ofprocesses is completed.

Working Effects of Embodiment

As heretofore described, the reference portion 80 of the transmissiongear 77 rotated in synchronization with the conveyance roller 60 isbrought into abutment with the carriage 41 moved to the end position,the carriage 41 is moved to the home position side, and the originposition of the conveyance roller 60 is detected by the linear encoder88 detecting the movement of the carriage 41. Therefore, it is possible,by making effective use of the transmission gear 77 and linear encoder88 included in the printer 11 for other purposes, to detect the originposition of the conveyance roller 60 without an accompanying increase insize or cost of the apparatus.

Also, in the embodiment, the correction value C corresponding to thecurrent rotation phase of the conveyance roller 60 is acquired based onthe origin position of the rotation phase of the conveyance roller 60detected by the controller 100, and on the correction value functionA(θ) stored in the EEPROM 104. The target rotation amount Xm iscorrected using the correction value C. The cyclical fluctuation in theamount of conveyance of the printing paper 50 is suppressed by theconveyance roller 60 being rotated by the target rotation amount Xmafter the correction. As a result, as the printing paper 50 isintermittently conveyed at approximately regular linefeed widths, it ispossible to record a neat image with no disturbance on the printingpaper 50.

Also, in the embodiment, as the flushing of the print head 42 is carriedout in the end position while the origin position of the conveyanceroller 60 is being detected, a clogging with ink due to the vicinity ofthe nozzles of the print head 42 drying while the position origin isbeing detected is prevented from occurring.

Also, in the embodiment, when the carriage 41 is moved to the endposition, the carriage 41 is in abutment with the reference portion 80of the transmission gear 77 and, when the linear encoder 88 detects nomovement of the carriage 41 even though the conveyance roller 60 isrotated one revolution, the conveyance roller 60 is rotated by arotation amount other than an integral multitude of one cycle, and thecarriage 41, after being moved to the home position, is moved to the endposition again, meaning that the carriage 41 is put into a condition inwhich it is not in abutment with the reference portion 80 of thetransmission gear 77 (an example of the rotating body). Therefore, theposition origin of the conveyance roller 60 is reliably detected.

In the embodiment, the reference potion 80 provided on the transmissiongear 77 has been taken to be one protruded from the surface 83 of thetransmission gear 77 in the width direction 121, but the referenceportion 80 may also be, for example, one depressed in the surface 83 ofthe transmission gear 77 in the width direction 121. Then, on thecarriage 41 being rotated in a condition in which it is pressed intocontact with the surface 83 of the transmission gear 77, and being movedby the reference portion 80 in the direction in which the referenceportion 80 is depressed, the movement of the carriage can be detected bythe linear encoder 88.

Also, in the embodiment, a description has been given of an embodimentin which the rotation amount of the conveyance roller 60 is detected bythe rotary encoder 89, but the rotation amount of the conveyance roller60 may also be detected using, for example, a magnetic sensor instead ofthe rotary encoder 89.

Also, in the embodiment, a description has been given of an embodimentin which the LF motor 85 is a DC motor, but the LF motor 85 may also bea stepping motor. In this case, there is no need for the rotary encoder89.

1. An image recording apparatus comprising: a conveyance roller whichconveys a recording medium along a conveyance path in a conveyancedirection; a print head which executes an image recording on therecording medium conveyed by the conveyance roller; a carriage which,being mounted with the print head, is configured to move in a movementdirection intersecting the conveyance direction; a sensor which ismounted with the carriage; and, an origin determiner configured todetermine an origin position of a rotation phase of the conveyanceroller based on a signal outputted, during the conveyance roller isrotated, from the sensor mounted with the carriage.
 2. The imagerecording apparatus according to claim 1, further comprising: an objectto be detected by the sensor mounted with the carriage; and a movingmechanism configured to relatively move the sensor and the object at atiming corresponding to the rotation phase of the conveyance roller. 3.The image recording apparatus according to claim 1, further comprising alinear encoder strip elongated in the movement direction of thecarriage, wherein the sensor is configured to sense the linear encoderstrip to output the signal.
 4. The image recording apparatus accordingto claim 1, wherein the sensor is disposed on a downstream of the printhead with respect to the conveyance path.
 5. The image recordingapparatus according to claim 2, wherein the moving mechanism isconfigured to move the carriage with the sensor at the timingcorresponding to the rotation phase of the conveyance roller.
 6. Theimage recording apparatus according to claim 5, wherein the movingmechanism comprises a rotating body which includes an abutment portionconfigured to abut the carriage at the timing corresponding to therotation phase of the conveyance roller.
 7. The image recordingapparatus according to claim 6, wherein the rotating body is configuredto rotate around a rotation axis of the conveyance roller.
 8. The imagerecording apparatus according to claim 1, wherein the sensor isconfigured to detect a light which changes corresponding to the rotationphase of the conveyance roller.
 9. An image recording apparatuscomprising: a conveyance roller which conveys a recording medium along aconveyance path in a conveyance direction; an encoder disk which isconfigured to rotate as the conveyance roller rotates; a print headwhich executes an image recording on the recording medium conveyed bythe conveyance roller; a carriage which, being mounted with the printhead, is configured to move in a movement direction intersecting theconveyance direction; a first sensor which is mounted with the carriageand is configured to output a first signal; a second sensor configuredto sense the encoder disk and to output a second signal; and, an origindeterminer configured to determine an origin position of a rotationphase of the conveyance roller based on the first signal outputted,during the conveyance roller is rotated, from the sensor mounted withthe carriage and on the second signal outputted from the second sensor.10. The image recording apparatus according to claim 9, furthercomprising: an object to be detected by the first sensor mounted withthe carriage; and a moving mechanism configured to relatively move thefirst sensor and the object at a timing corresponding to the rotationphase of the conveyance roller.
 11. The image recording apparatusaccording to claim 9, further comprising a linear encoder stripelongated in the movement direction of the carriage, wherein the firstsensor is configured to sense the linear encoder strip to output thefirst signal.
 12. The image recording apparatus according to claim 9,wherein the first sensor is disposed on a downstream of the print headwith respect to the conveyance path.
 13. The image recording apparatusaccording to claim 10, wherein the moving mechanism is configured tomove the carriage with the first sensor at the timing corresponding tothe rotation phase of the conveyance roller.
 14. The image recordingapparatus according to claim 13, wherein the moving mechanism comprisesa rotating body which includes an abutment portion configured to abutthe carriage at the timing corresponding to the rotation phase of theconveyance roller.
 15. The image recording apparatus according to claim14, wherein the rotating body is configured to rotate around a rotationaxis of the conveyance roller.
 16. The image recording apparatusaccording to claim 9, wherein the first sensor is configured to detect alight which changes corresponding to the rotation phase of theconveyance roller.